This invention relates to the field of navigation devices and more specifically to the field of high resolution directional orientation devices.
A liquid compass typically has a neutrally buoyant magnet assembly, which rotates in a fluid, to provide a directional indication of magnetic north. Such compasses are typically inexpensive, and sold as automobile accessories, or for personal use while hiking, etc.
Also known are compasses which employ a gimbal means to horizontally align a compass card regardless of the orientation of the outer casing. Typically, a gimballed compass utilizes light sensors and an encoded disc to relay positional information electrically through slip-rings. These compasses are expensive, and typically found in marine and aviation navigation apparatus.
U.S. Pat. No. 4,146,970 issuing on Apr. 3, 1979 to Robert Edwards is representative of a remote indicating magnet compass employing an optical shaft encoder responsive to earth's magnetic field.
U.S. Pat. No. 4,416,066 issuing on Nov. 22, 1983 to Bertold Romacker discloses an arrangement for orientation during journeys in land vehicles, which includes a means for ascertaining the distance covered by a vehicle, and a means for ascertaining the changes in direction of the vehicle, to determine the distance covered by the vehicle and/or the current location of the vehicle.
U.S. Pat. No. 4,132,113 issued on Jan. 2, 1979 to Harold Lyman, Jr. discloses a navigation device comprising a magnetic compass, utilizing a compass card having a varying pattern density, a light source, and pairs of sensors responsive to the varying pattern density, and a compensating means for craft pitch and roll.
U.S. Pat. No. 4,614,041 issued on Sep. 30, 1986 to Kenneth Darton discloses a magnetic angular position sensor having a ferrofluid filled spherical chamber in a cylindrical housing, having an odd number of permanent magnets, with Hall effect devices located in recesses in the ends of the cylindrical housing, with a magnetic flux detection means which is responsive to changes in the magnetic flux caused by rotation of the body within the chamber.
U.S. Pat. No. 4,588,992 issued on May 13, 1986 to William Clark discloses a radar tracking system and display comprising a ball type compass having an optical switching circuit for providing azimuth signals indicating the azimuth orientation of the radar unit. An inclinometer having an optical switching circuit for providing a target inclination signal used to determine a target altitude calculation.
U.S. Pat. No. 4,414,753 issuing on Nov. 15, 1983 to Michel Moulin et. al. discloses a process for compensating for the magnetic disturbances for determining a magnetic heading utilizing a computer to define a vector with a reference axis to determine an angle corresponding to the real magnetic heading of the vehicle or aircraft.
These devices all provide for orientation in a plane and provide for no information regarding magnetic declination or out of plane orientation. Also, these devices do not provide for high angular resolution when a shift in directional orientation occurs. It is the object of the present invention to provide both inclination and high angular resolution directional orientation.
Global Positioning Satellites (GPS) provide latitude and longitude with an accuracy tolerance of several meters. The present invention provides precise orientation within the accuracy tolerance of GPS devices. Movement and reorientation of a GPS receiver by a few meters would not be noted by a GPS since such a small movement is within the accuracy tolerance of the GPS receiver. The invention described herein is sensitive to movement and reorientation of a few millimeters.